Vibrational Energy Relaxation of Thiocyanate Ions in Liquid-to-Supercritical Light and Heavy Water. A Fermi's Golden Rule Analysis
Vibrational Energy Relaxation of Thiocyanate Ions in Liquid-to-Supercritical Light and Heavy Water. A Fermi's Golden Rule Analysis
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DOI：
10.1021/jz501710c
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发表时间：
2014-10-02
影响因子：
5.7
通讯作者：
Voehringer, Peter
中科院分区：
文献类型：
--
作者：
Czurlok, Denis;Gleim, Jeannine;Voehringer, Peter
本文研究了硫氰酸根离子在超快腈伸缩（nu（3））激发下的振动弛豫动力学。在两种溶剂中，阴离子的nu（3）= 1状态的弛豫导致振动基态的直接恢复，并且涉及过量振动能量到溶剂上的共振转移。在轻水中，能量接受态由弯曲-平动组合带（nu（B）+nu（L））提供，而在重水中，弛豫由来自拉伸-平动/限制平移热带（nu（S）-nu（L，T））的虚受主态热辅助。当从溶质和纯溶剂的线性红外光谱估计共振溶剂态密度时，发现弛豫速率严格遵守费米黄金法则。
The vibrational relaxation dynamics following an ultrafast nitrile stretching (nu(3)) excitation of thiocyanate anions dissolved in light and heavy water have been studied over a wide temperature and density range corresponding to the aqueous liquid up to the supercritical phase. In both solvents, the relaxation of the nu(3) = 1 state of the anion leads to a direct recovery of the vibrational ground state and involves the resonant transfer of the excess vibrational energy onto the solvent. In light water, the energy-accepting states are provided by the bending-librational combination band (nu(b) + nu(L)), while in heavy water, the relaxation is thermally assisted by virtual acceptor states derived from the stretching-librational/restricted translational hot band (nu(S) - nu(L,T)). The relaxation rate is found to strictly obey Fermi's Golden Rule when the density of resonant solvent states is estimated from the linear infrared spectra of the solute and the pure solvents.